1. Field of Invention
This invention relates to preventing and treating skin and nail infections using electromagnetic radiation.
2. Background of the Invention
The germicidal effects of electromagnetic radiation have been recognized for many years. Currently, electromagnetic radiation is being used more frequently at water and wastewater treatment plants to render water-borne pathogens harmless. Additionally, electromagnetic radiation is used to sterilize and purify air, particularly in laboratories and medical establishments. It is also used to sterilize equipment at such establishments. Electromagnetic radiation has been used for several years to sterilize and disinfect food products and has also been used to sanitize the hands to prevent the spread of germs to other persons.
However, the germicidal effects of electromagnetic radiation have not been recognized as a method for the prevention and treatment of skin and nail infections. Electromagnetic radiation is frequently combined with other additional chemical compositions to treat existing psoriasis, rashes, and other non-infectious skin disorders. It is believed that this type of treatment, termed phototherapy, is effective because it has an immunosuppressive effect that permits the body to heal itself. Recently, lasers alone have been successfully used to treat psoriasis by clearing localized chronic plaque. Phototherapy is also used to treat jaundice which is also a non-infectious disorder. However, no method of using electromagnetic radiation alone has been discovered to successfully treat existing microbial infections nor has electromagnetic radiation been used as a preventative treatment for infections.
Perceived Inability of Germicidal Radiation to Penetrate Skin and Nails
The main reason that electromagnetic radiation (also referred to as ‘radiation’ in this application) alone has not been used to prevent and treat skin and nail infections is that radiation generally considered germicidal is in the UVC range and has a perceived inability to penetrate the skin and nails deeply enough to inactivate the organisms that cause infection. It is well known that electromagnetic radiation cannot readily penetrate solid objects, particularly if the wavelength of such radiation is short. Very short wavelength light can even be absorbed by a relatively transparent media such as air. Ultraviolet light is a prime example of this with all of the ultraviolet C light (wavelength 100 to 280 nm) generated by the Sun being absorbed by the atmosphere before it reaches earth. Debris and other items also can prevent radiation from penetrating items. However, electromagnetic radiation can penetrate deep enough to inactivate organisms if it is applied for sufficient time and intensity. The Health Physics Society in its July 1998 paper titled “Ultraviolet Radiation and the Public Health” notes that “UVC, used in germicidal lamps, causes almost no damage because of its low penetration of the skin.” INTERSUN, the global UV project sponsored by the United Nations contains a graphic showing only 5% of UVC (at 254 nm) can penetrate to approximately a quarter of the depth of the epidermis and less than 1% can penetrate more than half the depth of the epidermis. Many other sources indicate that UVC cannot penetrate the skin or can do so only to a very limited depth. However, this depth is sufficient to treat infections since organisms are particularly susceptible to germicidal radiation. Also, with respect to nail infections, the additional radiation required to penetrate the nail is not harmful to the nail since it is composed of dead keratin.
UVC Dose Necessary to Inactivate Microbes
A second major reason the use of UV has not been contemplated are the relatively high doses necessary to kill some types of organisms. However, it has been found that it is not always necessary to kill organisms to render them harmless. It has been shown that organisms can be inactivated and rendered harmless using far less radiation than is necessary to kill them. Therefore, although its use as a treatment for has been overlooked in the past, electromagnetic radiation of sufficient strength can be used to treat human and animal infections.
There are several publications that note that organisms can be rendered harmless with less energy than is necessary to kill them. The inactivation of organisms by damaging RNA and DNA and preventing them from reproducing is a method used for disinfection of highly transparent potable water and is discussed in more detail in U.S. Pat. No. 6,129,893 (Bolton, 2000). The patent describes a method for preventing the replication of Cryptosporidium parvum using ultraviolet light. This patent indicates that ultraviolet light can inactivate bacteria at doses that are 3% to 10% of the dose necessary to actually kill the organisms. The method of inactivation is described as damage to the DNA and RNA that prevents the organisms from replicating. Since organisms are not long-lived in themselves, they are unable to continue to cause infection if they are unable to replicate. This discovery is applied to the inactivation of a pathogen in drinking water to render it safe for consumption. However, the method is only to irradiate one type of organism and then only in highly transparent drinking water.
The EPA guidance manual on Alternate Disinfectants and Oxidants (April 1999) devotes Chapter 8 to a discussion of germicidal UV as a disinfectant for drinking water. The manual notes that a UV wavelength of 240 to 280 nm is highly absorbed by the RNA and DNA of a microorganism. The absorbance of UV by the organisms results in the damage to the organism's ability to reproduce. The damage is often caused by the dimerization of pyrimidine molecules. This distorts the DNA helical structure. The EPA guidance manual also notes that the dose to inactivate 90% of most types of organisms is very low with a typical range of 2 to 6 mJ/cm2. The manuals notes that the germicidal radiation can be generated by a number of sources including a low pressure mercury lamp emitting at 254 nm, a medium pressure lamp emitting at 180 to 1370 nm, or lamps that emit at other wavelengths in a high intensity pulsed manner.
It should also be noted that it is not necessary to kill and inactivate all organisms in order to effect a cure for an infection. If a substantial amount of the organisms that have caused an infection are destroyed or rendered inactivated, the body's natural defenses will often work to clear the infection. Thus, doses of radiation necessary to effect a cure for an infection may be much lower than those necessary to sterilize an area by total destruction of all organisms.
Other Types of Germicidal Radiation
U.S. Pat. No. 5,900,211 (Dunn, 1999) also notes that it is not only UVC that can be used to sterilize water and food. Dunn discusses the use of pulsed polychromatic light to inactivate organisms. Dunn uses much lower amounts of energy to inactivate an organism than would be necessary to destroy it by excessive heat. However, Dunn applies this technology only to the sterilization of food and other materials and does not contemplate it for treatment of skin or nail infections. This is presumably because of the perceived inability of the light to penetrate the skin or nails (Dunn indicates that the effectiveness of the light is dependent on its ability to penetrate a medium effectively).
Prior Art Using UVC to Kill and Inactivate Organisms
U.S. Pat. No. 6,254,625 (Rosenthal, 2001) is an apparatus to sterilize hands to prevent the spread of infectious organisms. This apparatus makes use of light to sanitize the surface of the hands to prevent infections from spreading form person to person. In all of its embodiments it consists of at least two items. It make use of light to kill organisms along with either additional light to recuperatively heal the skin that has been irradiated or the use of ozone to increase the efficiency of killing organisms. The recuperative healing light uses the phenomenon of photoreactivation whereby cells and organisms that have been damaged can repair the damage using such light of a different wavelength. The inclusion of this source of light as part of the apparatus indicates that the disease causing organisms are killed and not merely inactivated otherwise they too could repair damage by photoreactivation. Additionally, the patent does not contemplate the use of the apparatus to treat an infected area of the skin and it makes no mention of treating any infection of the nails using electromagnetic radiation. The apparatus relies on the use of ozone to kill any organisms under the nails or shielded by debris and notes incorrectly that UVC radiation will not penetrate the nail. Rosenthal appears to be unaware that germicidal UV can penetrate the skin and nails and is used to treat infections.
U.S. Pat. No. 6,283,986 (Johnson, 2001) discusses the use of UVC radiation to treat wounds. However, Johnson only applies radiation to open wounds, which can be readily exposed, and notes that “given the short wavelength of UVC, no penetration of the underlying tissue would be expected.” The patent makes no mention of skin infections and mention of the nails is totally absent from the application although nail infections comprise a large part of total dermal infections. Possibly, the reason the patent only applies to wounds is that by their nature wounds are open and therefore capable of having their surfaces irradiated. It appears that Johnson is also unaware of the ability of germicidal radiation to penetrate the skin and nails.
It is the misconception that germicidal light cannot penetrate skin and nails which has in part prevented the discovery that germicidal radiation, including UVC, can indeed penetrate to a depth sufficient to be used successfully to treat skin and nail infections. While it is true that skin and nails will absorb a large percentage of UVC, enough can penetrate to successfully treat and prevent infections.
Nail Infections and Treatment
Nail infections are a particularly significant problem in the general population, affecting an estimated 5% of the overall population (approximately 15 million people). This percentage is significantly higher in the elderly age group and among athletes and other individuals who have high moisture in the area of their feet. Nail infections are often caused by fungus and this type of infection is termed onychomycosis. Currently, the preferred method for the prevention and treatment of skin and nail infections relies on application of topical medications or ingestion of medications. These medications are used to treat an existing infection, not for the prevention of an infection. Cost of treatment using medication can be between $600 and $1200 per course of treatment and can last three to six months. This is the amount of time it takes the medication to be incorporated into the nails. Another one to six months is then required for the nail to become free of infection. It should be noted that the cost noted above does not take into account doctors visits or diagnostic testing to determine if the patient can tolerate the medication (many medications can cause liver and other damage).
The problems associated with oral anti-fungal medications can be illustrated by several quotes from the clinical testing results for Itraconazole capsules (marketed under the trademark name SPORANOX® manufactured by Janssen Pharmaceutica, Inc.) which was the most prescribed anti-fungal in the U.S. in 1996. The success rate for treatment of onychomycosis of the toenail is reported as follows—“Results of these studies demonstrated mycological cure . . . in 54% of the patients. Thirty-five (35%) of patients were considered an overall success (mycologic cure plus clear or minimal nail involvement with significantly decreased signs) and 14% of patients demonstrated mycological cure (clearance of all signs, with or without residual nail deformity).” With respect to adverse reactions—“SPORANOX® has been associated with rare cases of serious hepatoxicity, including liver failure and death. Some of the cases had neither pre-existing liver disease nor a serious underlying medical condition.” In a study of 602 patients treated for systemic fungal disease, “treatment was discontinued in 10.5% of the patients due to adverse events.”
Although the current preferred method of treating nail infections is the use of oral medication, there are several other treatments in use. There are several topical applications that are used to treat fungal infections of the nails. However, these have an even poorer success rate than oral medications and the infections tend to re-occur.
U.S. Pat. No. 6,090,788 (Lurie, Jul. 8, 2000) is a patent to destroy fungal infections of the nails by introducing a pigment into an infected area and then to heating the pigment in the infected area with a laser in order to raise the temperature high enough to kill the organisms that have caused the infection by excessive heating. The energy listed in the preferred embodiments is from 5 to 15 J/cm2 and it has a relatively long wavelength (generally 500 to 700 nm) in order to penetrate the nail. The high amount of energy is great enough to cause excessive heating of the surrounding area thus destroying the organism. However, such high energy levels also have undesirable effects on the surrounding tissue such as redness and swelling.
Lurie incorrectly notes that typical fungi do not have pigment and, therefore, cannot absorb light. However, all cells will absorb light at a wavelength of between 240 and 280 nm since the DNA in the organism will absorb light at this wavelength. Also, Lurie is not cognizant of the fact that organisms can be inactivated at much lower doses that those necessary to destroy them by excessive heat. Due to the complicated nature of the treatment, U.S. Pat. No. 6,090,788 is proposed as a method to treat an infection, not to prevent one.
Lurie notes “there is a widely recognized need for, and it would be highly advantageous to have, a phototherapy method for treating skin and nail pathogens and a pharmaceutical composition to effect same.” It may be added that there is even a greater need to treat skin and nail infections using germicidal radiation only, particularly if said radiation could be effective at a much lower dose and not have the side effects associated with high energy lasers.